Some devices, including some mobile devices for example, receive data that may be pushed to them by a server. For example, a system may comprise a central message server that receives messages, such as electronic mail (“e-mail”) messages, addressed to a number of users. The system may, for example, further comprise support components for wireless communications such as a message management server, which processes messages that are received at the central message server and pushes the messages to mobile devices operated by the users. Generally, while messages may be stored on the central message server, the message management server may be used more specifically to control when, if, and how messages are to be sent to mobile devices. In this manner, messages may be forwarded to the users of mobile devices as they are received at the central message server, or in accordance with some other predefined schedule, or at some predefined interval, for example.
Where a server, such as the message management server, is adapted to push message data or other data to a mobile device, in some known implementations, the data is transmitted to the mobile device via a shared network infrastructure (e.g. the public Internet) and a wireless network. Such transmissions may be susceptible to interception and unauthorized access. In order to protect the confidentiality of these transmissions, data may be encrypted at the server prior to transmission, to be subsequently decrypted after the data is received at the mobile device. A key that is capable of decrypting encrypted data received from the server is usually stored on the mobile device. The key is typically downloaded to the mobile device during a synchronization process with a desktop computer, or when the mobile device is initially made ready for use, for example.
In the event that the key required to decrypt encrypted data received from the server is deleted, or becomes otherwise inaccessible, the received encrypted data cannot be decrypted until access to the key is restored. Furthermore, the server, unaware that the key has been deleted from the mobile device or has become otherwise inaccessible, may continue to push encrypted data to the mobile device. However, if, for example, the mobile device has been configured to discard data that it cannot decrypt, some data transmitted by the server to the mobile device may be lost.